Functionalized Photoinitiators

ABSTRACT

The invention relates to novel photoinitiators of formula (I) wherein each of the substituents is given the definition as set forth in the Specification and the claims. The photoinitiators can be used to prepare multifunctional photoinitiators.

The present invention relates to novel derivatives ofalpha-aminoketones, to their use as photoinitiators for thephotopolymerization of ethylenically unsaturated compounds and to theiruse to prepare multifunctional photoinitiators.

Alpha-aminoketone compounds are well known photoinitiators. Commerciallyavailable is for Example Irgacure 369® and Irgacure 907®.

Derivatives of alpha-aminoketones, which have an amino group in the4-position of the phenyl radical are described, for example, in EP138754 A2.

The European Patent Publication EP 284561 B1 describes photoinitiatorsof the formula Ar—CO—C(R₁R₂)—N(R₃R₄) or Ar—CO—C(R₁R₂)—X—C(R₁R₂)—CO—Ar orAr—CO—C(R₁NR₃R₄)—Y—C(R₁NR₃R)—CO—Ar, wherein Ar is e.g. phenyl optionallysubstituted by NR₇R₈.

The European Patent Publication EP 1 357 117 A2 describes novelaminoketone derivatives, obtainable by reacting1-{4-[bis-(2-hydroxy-ethyl)-amino]}-2-methyl-2-morpholino-1-propanone or2-(dimethylamino)-1-{4-[(2-hydroxyethyl)methylamino]-phenyl}-2-phenylmethyl-1-butanonewith ε-caprolactone.

U.S. Pat. No. 6,022,906 describes photoinitiators of the formulaY—X—Ar—CO—C(R₁R₂)—N(R₃R₄) provided that at least one of the radicals issubstituted by SH. These photoinitiators are prepared using, forexample,1-[4-(3-Hydroxypropylamino)phenyl]-2-dimethylamino-2-benzyl-propan-1-oneor1-[4-(3-Hydroxypropylamino)phenyl]-2-dimethylamino-2-benzyl-butan-1-one.These intermediate compounds have not been described as photoinitiators.

U.S. Pat. No. 4,992,547 discloses aminoarylketone photoinitiators of theformula Ar—CO—C(R₁R₂)—N(R₃R₄) e.g.2-methyl-1-[4-(N-(2-hydroxyethyl)-N-methylamino)phenyl]-2-dimethylaminopropan-1-one.

There is an increasing need to minimize the emission of volatile organiccomponents before curing and to minimize the migration and/or extractionof residual photoinitiator components from the cured product, whilemaintaining high initiator efficiency. For example, inks used inprinting on plastics food packaging should ideally meet the standardsfor minimization of extractable compounds from the coated and/or printedplastics. Such contamination can cause problems of taint and odor of thefoodstuff. Moreover, for other coating compositions, it is important tominimize migration of reactive materials, which may cause otherundesirable effects such as loss of adhesion to the substrate oryellowing.

One approach is to use photoinitiators of increased molecular size toreduce the level of migratable and/or extractable residualphotoinitiator components in a cured coating or ink composition. Suchpolymeric photoinitiators are, for example, disclosed in EP0 161 463 A1and include a commercially available compound, Fratelli-Lamberti's KIP100. However, polymeric photoinitiators are often high viscose, whichmakes the handling difficult.

The problem to be solved by the present invention is the provision ofalpha-aminoketone photoinitiators having a high reactivity, a low odor,a low migration and in addition are able to react with the reagentslisted in the application such as e.g. with acids, aldehydes, ketonesand the like, to build up multifunctional photoinitiators.

The invention relates to photoinitiators of the formula I

wherein

-   n is 1 or 2;-   L is a linker;-   X is —O—, —S— or —NR₃₂—;-   Z is a direct bond, —CH₂—, —O—, —S— or —NR₁₀—;-   R₁ is    -   (a) linear or branched C₁-C₁₂-alkyl, which is unsubstituted or        substituted by one or more of the groups C₁-C₄-alkyoxy, phenoxy,        halogen or phenyl;    -   (b) a radical of the formula

-   -   (c) a radical of the formula

where q is 0, 1, 2 or 3; or

-   -   (d) a radical of the formula

where Ar is phenyl, which is unsubstituted or substituted by one or moreof the groups halogen, OH, NO₂, —N(R₁₀)₂, C₁-C₁₂-alkyl, C₁-C₄-alkyl thatis additionally substituted by OH, halogen, N(R₁₀)₂, C₁-C₁₂-alkoxy,—COO(C₁-C₁₈-alkyl), —CO(OCH₂CH₂)_(n)OCH₃ or —OCO(C₁-C₄-alkyl);C₁-C₁₂-alkyoxy, C₁-C₄-alkyoxy that is additionally substituted by—COO(C₁-C₁₈-alkyl) or —CO(OCH₂CH₂)_(n)OCH₃; —OCO(C₁-C₄-alkyl),C₁-C₈-alkylthio, phenoxy, —COO(C₁-C₁₈-alkyl), —CO(OCH₂CH₂)_(n)OCH₃,phenyl or benzoyl; where n is 1-20;

-   R₂ if n is 1, independently of R₁ has one of the meanings of R₁; or-   R₁ together with R₂ forms a ring of the formula

where m is 1 or 2;

-   R₂ if n is 2, is a direct bond, C₂-C₁₆-alkylene, cyclohexylene,    xylylene, dihydroxyxylylene, C₄-C₈-alkenediyl, C₆-C₁₀-alkadienediyl    or dipentenediyl;-   R₃ is hydrogen, C₁-C₁₂-alkyl, C₂-C₄-alkyl substituted by one or more    of the groups hydroxy, C₁-C₄-alkoxy, —CN, —COO(C₁-C₄-alkyl);    C₃-C₅-alkenyl, C₅-C₁₂-cycloalkyl or C₇-C₉-phenylalkyl;-   R₄ is C₁-C₁₂-alkyl, C₂-C₄-alkyl substituted by one or more of the    groups hydroxy, C₁-C₄-alkoxy, —CN, —COO(C₁-C₄-alkyl); C₃-C₅-alkenyl,    C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, phenyl; or R₄ and R₂ together    is C₁-C₇-alkylene, C₇-C₁₀-phenylalkylene, o-xlylene, 2-butenylene or    C₂-C₃-oxa- or azaalkylene; or R₄ and R₃ together is C₃-C₇-alkylene    that may be interrupted by —O—, —S—, —CO— or —N(R₁₃)— and    substituted by hydroxy, C₁-C₄-alkoxy or —COO(C₁-C₄-alkyl);-   R₅ is hydrogen or C₁-C₄-alkyl; or R₅ together with R₃₀ is    C₁-C₂-alkylene;-   R₆ is hydrogen, C₁-C₈-alkyl or phenyl;-   R₇, R₈ and Rg independently of each other are hydrogen or    C₁-C₄-alkyl, or R₇ and R₈ together are C₃-C₇-alkylene;-   R₁₀ is hydrogen, C₁-C₈-alkyl, C₃-C₅-alkenyl, C₇-C₉-phenlyalkyl,    C₁-C₄-hydroxyalkyl or phenyl;-   R₁₁ and R₁₂ independently of each other are hydrogen or C₁-C₄-alkyl,    or R₁₁ and R₁₂ together are C₃-C₇-alkylene;-   R₁₃ is hydrogen, C₁-C₁₂-alkyl, which may be interrupted by one or    more —O— or C₃-C₅-alkenyl, C₇-C₉-phenylalkyl, C₁-C₄-hydroxyalkyl,    —CH₂CH₂CN, —CH₂CH₂COO(C₁-C₄-alkyl), C₂-C₈-alkanoyl, or benzoyl;-   R₃₀ and R₃₁ independently of one another are hydrogen, C₁-C₁₈-alkyl    or C₁-C₁₈-alkyl substituted by hydroxy, C₁-C₄-alkoxy,    —O—CO—(C₁-C₄-alkyl), —CN and/or —COO(C₁-C₄-alkyl); C₃-C₁₈-alkenyl,    C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, C₂-C₁₈-alkanoyl, benzoyl or    norbornenoyl; or C₂-C₁₈-alkanoyl, benzoyl or norbornenoyl    substituted by C₁-C₄-alkoxy, —NR₃₃R₃₄, —SR₃₅, —COOH or    —COO(C₁-C₄-alkyl); or benzoyl or norbornenoyl substituted by    hydroxy, or C₃-C₅-alkenoyl, —SO₂—(C₁-C₁₂-alkyl) or    —SO₂—(C₁-C₁₂-alkylphenyl); or —CO—NH—C₁-C₁₂-alkyl or    —CO—NH—(C₀-C₁₂-Alkylen)—N═C═O optionally interrupted by one or two    phenylene, methylphenylene, phenylene-O-phenylene, cyclohexanediyl,    methylcyclohexanediyl, trimethylcyclohexanediyl, norbornanediyl,    [1-3]diazetidine-2,4-dione-1,3-diyl,    3-(6-isocyanatohexyl)-biuret-1,5-diyl or    5-(6-isocyanatohexyl)-[1,3,5]triazinan-2,4,6-trion-1,3-diyl; or-   R₃₀ and R₃₁ together with the group —N—L—X form cyclic structures    selected from

R₃₂ is hydrogen, C₁-C₁₈-alkyl or C₁-C₁₈-alkyl substituted by hydroxy,C₁-C₄-alkoxy, —O—CO—(C₁-C₄-alkyl), —CN and/or —COO(C₁-C₄-alkyl);C₃-C₁₈-alkenyl, C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, C₂-C₁₈-alkanoyl,benzoyl or norbornenoyl; or C₂-C₁₈-alkanoyl benzoyl or norbornenoylsubstituted by hydroxy, C₁-C₄-alkoxy, —NR₃₃R₃₄, —SR₃₅, —COOH or—COO(C₁-C₄-alkyl); or C₃-C₅-alkenoyl, —SO₂—(C₁-C₁₂-alkyl) or—SO₂—(C₁-C₁₂-alkylphenyl); or —CO—N—C₁-C₁₂-alkyl or—CO—NH—(C₀-C₁₂-Alkylen)—N═C═O optionally interrupted by one or twophenylene, methylphenylene, phenylene-O-phenylene, cyclohexanediyl,methylcyclohexanediyl, trimethylcyclohexanediyl, norbornanediyl,[1-3]diazetidine-2,4-dione-1,3-diyl,3-(6-isocyanatohexyl)-biuret-1,5-diyl or5-(6-iso-cyanatohexyl)-[1,3,5]triazinan-2,4,6-trion-1,3-diyl;

-   R₃₃ and R₃₄ independently of one another are hydrogen, C₁-C₁₂-alkyl,    C₂-C₄-hydroxy-alkyl, C₃-C₁₀-alkoxyalkyl, C₃-C₅-alkenyl,    C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, phenyl, C₂-C₁₈-alkanoyl or    benzoyl; or R₃₃ and R₃₄ together are C₂-C₈-alkylene optionally    interrupted by —O—, —S— or —NR₃₆—, or are C₂-C₈-alkylene optionally    substituted by hydroxy, C₁-C₄-alkoxy, —O—CO—(C₁-C₄-alkyl), or —COO(    C₁-C₄-alkyl);-   R₃₅ is C₁-C₁₈-alkyl, hydroxyethyl, 2,3-dihydroxypropyl, cyclohexyl,    benzyl, phenyl, C₁-C₁₂-alkylphenyl, —CH₂—COO(C₁-C₁₈-alkyl),    —CH₂CH₂—COO(C₁-C₁₈-alkyl) or —CH(CH₃)—COO(C₁-C₁₈-alkyl);

R₃₆ is hydrogen, C₁-C₁₂-alkyl optionally interrupted by one or more noadjacent —O-atoms, C₃-C₅-alkenyl, C₇-C₉-phenylalkyl, C₁-C₄-hydroxyalkyl,—CH₂CH₂CN, —CH₂CH₂COO(C₁-C₄-alkyl), C₂-C₁₂-alkanoyl or benzoyl;

with the proviso that the following compounds are excluded:

Definitions

Suitable linkers are linear or branched C₂-C₁₈-alkanediyl, orC₂-C₃₀-alkanediyl optionally interrupted by one or more not adjacentO-atoms, and/or optionally substituted by one or more hydroxy atoms.Other suitable linkers are 1,3-cyclohexanediyl, 1,4-cyclohexanediyl,4-methyl-1,3-cyclohexanediyl or are selected form the followingstructures.

In the present description the term “alkyl”, alone or in combination,signifies a straight-chain or branched-chain alkyl group; the upper andlower limits of the number of carbon atoms is given in each case.

The term “alkoxy”, alone or in combination, signifies a group of theformula alkyl-O-in which the term “alkyl” has the previously givensignificance.

The term “alkenyl”, alone or in combination, means a straight-chain orbranched-chain hydrocarbon radial having one or more double bonds andcontaining a number of carbon atoms as given.

The term “alkanoyl”, alone or in combination, means an acyl radicalderived from an alkanecarboxylic acid wherein alkane means a radical asdefined above for alkyl. Examples of alkanoyl radicals include acetyl,propionyl, butyryl, valeryl, 4-methylvaleryl, and the like.

The term “alkenoyl”, alone or in combination, means an acyl radicalderived from an alkenecarboxylic acid wherein alkene means a radical asdefined above for alkenyl.

The term “alkadiene” alone or in combination includes compounds with atleast two carbon to carbon double bonds and containing a number ofcarbon atoms as given.

All these compounds have at least one basic amino group and cantherefore be converted into the corresponding salts by addition ofacids. The acids can be inorganic or organic acids. Examples of suchacids are HCl, HBr, H₂SO₄, H₃ PO₄, mono- or polycarboxylic acids, forexample, acetic acid, oleic acid, succinic acid, sebacic acid, tartaricacid or CF₃ COOH, and sulfonic acids, for example, CH₃SO₃H.

Preferred Photoinitiators

A compound of the formula I, wherein

-   n is 1 or 2;-   L is a linker;-   X is —O—, —S— or —NR₃₂—-   Z is a direct bond;-   R₁ is    -   (a) linear or branched unsubstituted C₁-C₁₂-alkyl;    -   (b) a radical of the formula;

or

-   -   (d) a radical of the formula

wherein Ar is phenyl, which is unsubstituted or substituted by one ormore of the groups NO₂, —N(R₁₀)₂, C₁-C₄-alkyl, C₁-C₄-alkoxy,C₁-C₄-alkylthio, phenoxy;

-   R₂ if n is 1, independently of R₁ has one of the meanings of R₁;-   R₂ if n is 2, is C₂-C₈alkylene;-   R₃ is C₁-C₄-alkyl, C₂-C₄-alkyl substituted by hydroxy, C₁-C₄-alkoxy;    C₃-C₅-alkenyl;-   R₄ independently of R₃ has one of the meanings of R₃; or R₄ together    with R₃ is C₄-C₅-alkylene that may be interrupted by —O—, —N(R₁₃)—;-   R₅ is hydrogen;-   R₆, R₇, R₈ and Rg independently of each other are hydrogen or    methyl;-   R₁₀ is hydrogen, C₁-C₄-alkyl or C₃-C₅-alkenyl;-   R₁₃ is hydrogen or C₁-C₄-alkyl;-   R₃₀ and R₃₁ independently of one another are hydrogen, C₁-C₁₂-alkyl;    or C₂-C₆-alkyl substituted by hydroxy, C₁-C₄-alkoxy,    —O—CO—(C₁-C₄-alkyl), or —COO( C₁-C₄-alkyl); allyl, cyclohexyl or    C₇-C₉-phenylalkyl; or C₂-C₁₂-alkanoyl, benzoyl or norbornenoyl; or    C₂-C₁₂-alkanoyl, benzoyl or norbornenoyl substituted by    C₁-C₄-alkoxy, —COOH or —COO(C₁-C₄-alkyl); or C₃-C₅-alkenoyl; or    —CO—NH—C₁-C₁₂-alkyl or —CO—NH—(C₀-C₁₂-alkylen)—N═C═O, optionally    interrupted by one or two phenylene,methylphenylene,    phenylene-O-phenylene, cyclohexanediyl, methylcyclohexanediyl,    trimethylcyclohexanediyl, norbornanediyl,    [1-3]diazetidine-2,4-dione-1,3-diyl,    3-(6-isocyanatohexyl)-biuret-1,5-diyl or    5-(6-lsocyanatohexyl)-[1,3,5]triazinane-2,4,6-trione-1,3-diyl;-   R₃₂ is hydrogen or C₁-C₁₂-alkyl.

Especially preferred are compounds of the formula I, wherein

-   n is 1 or 2;-   L is linear or branched C₂-C₁₈-alkanediyl;-   X is —O—;-   Z is a direct bond;-   R₁ is    -   (a) linear or branched unsubstituted C₁-C₃-alkyl;    -   (b) a radical of the formula;

-   -   (d) a radical of the formula

where Ar is phenyl, which is unsubstituted or substituted by CH₃—NO₂ or—N(R₁₀)₂;

-   R₂ if n is 1, independently of R₁ has one of the meanings of R₁;-   R₂ if n is 2, is C₂-C₈alkylene;-   R₃ is methyl,-   R₄ is methyl or R₄ together with R₃ is C₅-alkylene that is    interrupted by —O—;-   R₅ is hydrogen;-   R₆, R₇, R₈ and R₉ are hydrogen;-   R₁₀ is hydrogen;-   R₃₀ and R₃₁ independently of one another are hydrogen, C₁-C₁₂-alkyl;    or C₂-C₆-alkyl substituted by hydroxy; C₁-C₄-alkoxy,    —O—CO—(C₁-C₄-alkyl), or C₃-C₅-alkenoyl.

An especially high reactivity is obtained by photoinitiators of theformula I, wherein R₁ is benzyl, 4-aminobenzyl, propyl or allyl and R₂is ethyl or is C₂-C₈alkylene.

EXAMPLES

Preparation of the Novel Photoinitiators

The compounds of formula I can be prepared starting from known ketonesby C-alkylation or C-benzylation. The amino group —NR₃R₄ is preferablyintroduced before the alkylation or benzylation. The synthesis iscarried out in the sequence of reaction steps as described in EPO284561B1 or U.S. Pat. No. 5,077,402.

For example, a halogeno aryl ketone such as e.g. 4-fluorobutyrophenonecan be used as starting ketone. After bromination the dimethylaminogroup is introduced followed by.a benzylation reaction. The halogen isthen replaced by ethanolamine in a nucleophilic replacement reaction.The following key compound is obtained.

The above key compound (Ex. 1, named Educt E) or the compounds accordingto Examples 2-18 can be further reacted with reagents such as thoselisted below. The radical R in the following lists may carry 1-n of thefunctional groups indicated. If n>1, the polyfunctional reagent may bereacted with 1-n equivalents of the educt (e.g. E).

Reagents with which E can be reacted are:

-   1) acids, acid halides, linear or branched acid anhydrides, COCl₂ or    lactones Educt E and R—COOH, R—COCl, R—CO—O—CO—R,

Amides (A), esters (B) or amide-ester compounds (AB), (ABR) areobtained.

Examples of cyclic amide-ester compounds (ABR) are:

-   2) Reaction with aldehydes or ketones

Educt E and R—CHO, R—CO—R

2-Oxazolidine compounds (A) or 2-oxazolidine compounds (B) and furthercyclic products are obtained.

-   3) Reaction with isocyanates

Educt E and R—N═C═O

Urea derivatives (A) or urethane derivatives (B) or urea-urethanederivatives (AB) or cyclic urea-urethane derivatives (ABR) are obtained.

-   4) Reaction with sulfonic acid chloride.

Educt E and R—SO₂—Cl

Sulfonamide derivatives (A), sulfonic acid esters (B) orsulfonamide-sulfonic acid derivatives (AB) are obtained.

-   5) Alkylation, reaction with R—X

Educt E and R-halogen or R—O—SO₂—R′ or other known alkylations agents,

Amines (A), ethers (B) or amine-ether derivatives (AB) are obtained.

Examples are:

The compounds thus obtained can in turn be used as starting materials E′for as described under 1), 2), 3), 4), 6), 7) or 8)

-   6) Reaction with epoxides or epichlorhydrine

Educt E and

Hydroxyalkylamine compounds (A) or hydroxyalkylether compounds (B) orhydroxyalkylamine-hydroxyalkylether-compounds (AB) or cyclichydroxyalkylamine-hydroxyalkylether-compounds (ABR) are obtained.

-   7) Reaction with acrylates or methacrylates

Educt E and CH₂═CH—CO—OH or CH₂═C(CH₃)—CO—OH or with the correspondingacid chlorides.

Acrylamides (A) or acrylester (B) or amide-ester-compounds (AB) areobtained.

Examples for cyclic compounds obtained from the above compounds byintramolecular Michael addition reaction.

-   7a) The acrylamides (A), acrylester (B) or amide-ester compounds    (AB) can be reacted with amines to obtain

-   7b) The acrylamides (A), acrylester (B) or amide-ester compounds    (AB) can be reacted with alcohols to obtain

-   7c) The acrylamides (A), acrylester (B) or amide-ester compounds    (AB) can be reacted with thioalcohols to obtain

Examples of multifunctional photoinitiators are:

Dimeric or Oligomeric Products

The compounds of Examples 1-18 may be reacted with following acidhalides, acid anhydrides, di-or poly carboxylic acids, di-orpolyaldehydes, di- or oligoisocyanates, di-or oligoepoxides, di-orpolyamines, di-or oligoalcohols, di-or polythiols to obtain di-oroligomeric product.

Technical important acid chlorides:

Technical important acid anhydrides:

Technical important di-or polycarboxylic acids

Technical important di-or polyaldehydes

Technical important di-or polyisocyanates

Technical important di-or polyepoxides:

Technical important di-or polyamines:

Technical important di-or polythiols:

Technical important di-or polyalcohols:

Si-containing di-and oligoalcohols.

Si-containing di- and oligo-lactone-derivates

Linking moieties between initiator and Si

Examples for the alkylation at the N-atom are:

According to the invention, the compounds of the formula I can be usedas photoinitiators for photopolymerization of ethylenically unsaturatedcompounds or mixtures containing such compounds.

Thus, the invention relates also to a composition comprising

-   (A) at least one ethylenically unsaturated compound,-   (B) a photoinitiator of formula I as defined above.

Suitable Ethylenically Unsaturated Compounds (A)

Suitable compounds with olefinic double bonds are all compounds that canbe crosslinked by free radical polymerization of the double bond. Theethylenically unsaturated compound may be a monomer, an oligomer or aprepolymer, a mixture thereof or a copolymer thereof.

Monomers suitable for free-radical polymerization are, for example,ethylenically unsaturated polymerizable monomers selected from the groupconsisting of (meth)acrylates, alkenes, conjugated dienes, styrenes,acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleicanhydride, fumaric anhydride, (meth)acrylic acid, (meth)acrylic acidderivatives such as esters and amides, vinyl halides and vinylidenehalides. Preferred are compounds having (meth)acryloyl, vinyl and/ormaleinate groups. Especially preferred are (meth)acrylates.

Compounds which contain free-radically polymerizable double bonds in theform of the preferred (meth)acryloyl groups may be produced inaccordance with conventional methods. This may proceed, for example, by:transesterifying OH-functional resins, such as OH-functional polyesters,polyacrylates, polyurethanes, polyethers or epoxy resins, with alkylesters of (meth)acrylic acid; esterifying the stated OH-functionalresins with (meth)acrylic acid; reacting the stated OH-functional resinswith isocyanate-functional (meth)acrylates; reacting acid-functionalresins, such as polyesters, polyacrylates, polyurethanes withepoxy-functional (meth)acrylates; reacting epoxy-functional resins, suchas polyesters, poly-acrylates, epoxy resins with (meth)acrylic acid.These production methods stated by way of example are described in theliterature and known to the person skilled in the art.

According to the invention, the compounds of the formula I can be usedas photoinitiators for photopolymerization of ethylenically unsaturatedcompounds or mixtures containing such compounds.

Thus, the invention relates also to a composition comprising

-   (A) at least one ethylenically unsaturated compound,-   (B) a photoinitiator of formula I as defined above.

Suitable Ethylenically Unsaturated Compounds (A)

Suitable compounds with olefinic double bonds are all compounds that canbe crosslinked by free radical polymerization of the double bond. Theethylenically unsaturated compound may be a monomer, an oligomer or aprepolymer, a mixture thereof or a copolymer thereof.

Monomers suitable for free-radical polymerization are, for example,ethylenically unsaturated polymerizable monomers selected from the groupconsisting of (meth)acrylates, alkenes, conjugated dienes, styrenes,acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleicanhydride, fumaric anhydride, (meth)acrylic acid, (meth)acrylic acidderivatives such as esters and amides, vinyl halides and vinylidenehalides. Preferred are compounds having (meth)acryloyl, vinyl and/ormaleinate groups. Especially preferred are (meth)acrylates.

Compounds which contain free-radically polymerizable double bonds in theform of the preferred (meth)acryloyl groups may be produced inaccordance with conventional methods. This may proceed, for example, by:transesterifying OH-functional resins, such as OH-functional polyesters,polyacrylates, polyurethanes, polyethers or epoxy resins, with alkylesters of (meth)acrylic acid; esterifying the stated OH-functionalresins with (meth)acrylic acid; reacting the stated OH-functional resinswith isocyanate-functional (meth)acrylates; reacting acid-functionalresins, such as polyesters, polyacrylates, polyurethanes withepoxy-functional (meth)acrylates; reacting epoxy-functional resins, suchas polyesters, poly-acrylates, epoxy resins with (meth)acrylic acid.These production methods stated by way of example are described in theliterature and known to the person skilled in the art.

Examples of prepolymers or oligomers include (meth)acryloyl-functional(meth)acrylic copolymers, polyurethane (meth)acrylates, polyester(meth)acrylates, unsaturated poly-esters, polyether (meth)acrylates,silicone (meth)acrylates and epoxy resin (meth)acrylates havingnumber-average molecular masses from, for example, 500 to 10,000,preferably 500 to 5,000.

The (meth)acryloyl-functional prepolymers may be used in combinationwith reactive diluents, i.e., free-radically polymerizable low molecularweight compounds with a molar mass of below 500 g/mol. The reactivediluents may be mono-, di- or polyunsaturated. Examples ofmonounsaturated reactive diluents are (meth)acrylic acid and the estersthereof, maleic acid and the esters thereof, vinyl acetate, vinyl ether,substituted vinyl ureas, styrene, vinyltoluene. Examples ofdiunsaturated reactive diluents are di(meth)acrylates such as alkyleneglycol di(meth)acrylate, polyethylene glycol di(meth)acrylate,1,3-butanediol di-(meth)acrylate, vinyl (meth)acrylate, allyl(meth)acrylate, divinylbenzene, dipropylene glycol di(meth)acrylate,hexanediol di(meth)acrylate. Examples of polyunsaturated reactivediluents are glycerol tri(meth)acrylate, trimethylolpropanetri(meth)acrylate, pentaerythritol tri(meth)-acrylate, pentaerythritoltetra(meth)acrylate. The reactive diluents may be used alone or inmixture.

Suitable salts of acrylic acid or methacrylic acid are, for example,(C₁-C₄alkyl)₄ammonium or (C₁-C₄alkyl)₃NH salts, e.g. thetetramethylammonium, tetraethylammonium, trimethylammonium ortriethylammonium salt, the trimethyl-2-hydroxyethylammonium ortriethyl-2-hydroxy-ethylammonium salt, thedimethyl-2-hydroxyethylammonium or diethyl-2-hydroxyethylammonium salt.

The ethylenically unsaturated compounds may contain, in addition to theolefinic double bonds, one or more further, identical or differentfunctional groups. Examples of functional groups include hydroxyl,isocyanate (optionally blocked), N-methylol, N-methylolether, ester,carbamate, epoxy, amino (optionally blocked), acetoacetyl, alkoxysilyland carboxyl groups. Examples are polyurethane resins with(meth)acryloyl groups and glycerol mono-and di-(meth)acrylate,trimethylol propane mono-and di(meth)acrylate or pentaerythritoltri(meth)-acrylate.

The photopolymerisable compounds (A) can be used on their own or in anydesired mixture.

Additives

The above-described compositions may further comprise customaryadditives, which may, as an alternative, also be added after thepolymerization. Such additives can be added in small amounts, e.g.UV-absorbers or light stabilizers, e.g. compounds selected from thegroup consisting of hydroxyphenylbenzotriazoles,hydroxyphenylbenzophenones, oxalamides and hydroxyphenyl-s-triazines.Particularly suitable light stabilizers are those selected from thegroup consisting of N-alkoxy-Hals compounds such as Tinuvin 123, or ofsterically hindered amines Hals compounds of the2-(2-hydroxyphenyl)-1,3,5-triazine or 2-hydroxyphenyl-2H-benzotriazoletype. Examples of light stabilizers of the2-(2-hydroxyphenyl)-1,3,5-triazine type are known from the patentliterature, e.g. U.S. Pat. No. 4,619,956, EP-A-434 608, U.S. Pat. No.5,198,498, U.S. Pat. No. 5,322,868, U.S. Pat. No. 5,369,140,U.S. Pat.No. 5,298,067, WO-94/18278;EP-A-704 437, GB-A-2,297,091 or WO-96/28431.3,3,5,5 polysubstituted morpholin-2-one derivatives as described in U.S.Pat. No. 6,140,326 are well established light stabilizers for coatings.

The compositions may further comprise other customary additives such asleveling agents, rheology-influencing agents, such as, fine-particlesilicic acid, layer silicates, urea compounds; thickeners, e.g., basedon partially cross-linked carboxy-functional polymers or polyurethanes;defoamers, wetting agents, anti-crater agents, degassing agents, e.g.,benzoin, antioxidants.

The compounds may further comprise additives to improve the storagestability such as polymerization inhibitors on nitroxyl basis, e.g.Irgastab UV10 and 2,2,6,6-tetramethyl-4-hydroxy-piperidin-1-oxyl(4-hydroxy-TEMPO).

The photoinitaitors of the formula I are suitable in double-curing andin dual curing systems.

Double-Curing

Double curable systems comprise ethylenically unsaturated monomers,which can be polymerized by UV radiation or which can be polymerizedthermally induced by IR or NIR radiation or by convection heat. Indouble curable systems in addition to the photoinitiator, a thermalinitiator is present. Any thermal initiator known in the art may beused. Preferably, the additional thermal initiators are peroxides suchas dialkyl peroxides, dicumyl peroxide, peroxo carboxylic acids and soone and azo initiators as disclosed in U.S. Pat. No. 5,922,473.

Dual-Curing

Dual curable systems comprise ethylenically unsaturated monomers, whichcan be polymerized thermally induced by IR or NIR radiation or byconvection heat. Furthermore, at least one second thermal crosslinkablecompound is present. The second compound preferably crosslinks via apolyol-isocyanate reaction to form a polyurethane.

The composition may contain fillers and/or transparent, color- and/orspecial effect-imparting pigments and/or soluble dyes. Examples ofinorganic or organic color-imparting pigments include titanium dioxide,micronized titanium dioxide, iron oxide pigments, carbon black, azopigments, phthalocyanine pigments, quinacridone or pyrrolopyrrolepigments. Examples Qf special effect-imparting pigments include metallicpigments, e.g., of aluminum, copper or other metals; interferencepigments, such as, metal oxide-coated metallic pigments, e.g., titaniumdioxide-coated or mixed oxide-coated aluminum, coated mica, such as,titanium dioxide-coated mica and graphite special-effect pigments.Examples of suitable fillers include silica, aluminum silicate, bariumsulfate, calcium carbonate and talc.

In addition to the photoinitiator of formula I annother knownphotoinitiator may be present, for example, α-hydroxyketones andα-aminoketones, phenylglyoxalates or phospine oxides are photoinitiatorscommonly used in graphic arts applications.

Especially preferred are, for example, the following commerciallyavailable photoinitiators:

Darocur 1173: 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP) andOligomeric HMPP,

Irgacure 184: 1-hydroxy-cyclohexyl-phenylketone,

Irgacure 2959:2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone,

Irgacure 369:2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone,

Irgacure 1300: Irgacure 369+Irgacure 651 (benzildimethylketal),

Irgacure 379:2-(4-Methylbenzyl)-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone,

Irgacure 127:2-Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one,

Irgacure 754: oxo-phenyl-acetic acid1-methyl-2-[2-(2-oxo-2-phenyl-acetoxy)-propoxy]-ethyl ester,

Irgacure 819: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,

Irgacur 250: 4-isobutylphenyl-4′-methylphenyl iodoniumhexafluorophosphate,

Darocur ITX: 2-isopropylthioxanthone and 4-isopropylthioxanthone,

Darocur EDB: ethyl-4-dimethylamino benzoate,

Darocur EHA: 2-ethylhexyl-4-dimethylamino benzoate; or mixtures of theabove photoinitiators.

The photopolymerisable compositions comprise the photoinitiatoradvantageously in an amount from 0.05 to 15% by weight, preferably from0.1 to 8% by weight, based on the composition.

In dual curing systems at least one second thermal crosslinkablecompound is present selected from

-   1. surface coatings based on cold- or hot-crosslinkable alkyd,    acrylate, polyester, epoxy or melamine resins or mixtures of such    resins, optionally with the addition of a curing catalyst;-   2. two-component polyurethane surface coatings based on    hydroxyl-group-containing acrylate, polyester or polyether resins    and aliphatic or aromatic isocyanates, isocyanurates or    polyisocyanates;-   3. two-component polyurethane surface coatings based on    thiol-group-containing acrylate, polyester or polyether resins and    aliphatic or aromatic isocyanates, isocyanurates or polyisocyanates;-   4. one-component polyurethane surface coatings based on blocked    isocyanates, isocyanurates or polyisocyanates which are deblocked    during stoving; the addition of melamine resins is also possible, if    desired;-   5. one-component polyurethane surface coatings based on aliphatic or    aromatic urethanes or polyurethanes and hydroxyl-group-containing    acrylate, polyester or polyether resins;-   6. one-component polyurethane surface coatings based on aliphatic or    aromatic urethane acrylates or polyurethane acrylates having free    amine groups in the urethane structure and melamine resins or    polyether resins, optionally with the addition of a curing catalyst;-   7. two-component surface coatings based on (poly)ketimines and    aliphatic or aromatic isocyanates, isocyanurates or polyisocyanates;-   8. two-component surface coatings based on (poly)ketimines and an    unsaturated acrylate resin or a polyacetoacetate resin or a    methacrylamidoglycolate methyl ester;-   9. two-component surface coatings based on carboxyl- or    amino-group-containing polyacrylates and polyepoxides;-   10. two-component surface coatings based on    anhydride-group-containing acrylate resins and a polyhydroxy or    polyamino component;-   11. two-component surface coatings based on acrylate-containing    anhydrides and poly-epoxides;-   12. two-component surface coatings based on (poly)oxazolines and    anhydride-group-containing acrylate resins or unsaturated acrylate    resins or aliphatic or aromatic isocyanates, isocyanurates or    polyisocyanates;-   13. two-component surface coatings based on unsaturated    (poly)acrylates and (poly)-malonates;-   14. thermoplastic polyacrylate surface coatings based on    thermoplastic acrylate resins or extrinsically crosslinking acrylate    resins in combination with etherified melamine resins;-   15. surface-coating systems, especially clearcoats, based on    malonate-blocked isocyanates with melamine resins (e.g.    hexamethoxymethylmelamine) as crosslinkers (acid-catalysed);-   16. UV-curable systems based on oligomeric urethane acrylates and/or    acylate acrylates, optionally with the addition of other oligomers    or monomers;-   17. dual-cure systems, which are cured first thermally and then by    UV, or vice versa, the constituents of the surface-coating    formulation containing double bonds that can be caused to react by    UV light and photoinitiators and/or by electron-beam curing.

The resulting coating materials of the invention may be conventionalcoating materials, containing organic solvents, aqueous coatingmaterials, substantially or fully solvent-free and water-free liquidcoating materials (100% systems), substantially or fully solvent-freeand water-free solid coating materials (powder coating materials), orsubstantially or fully solvent-free powder coating suspensions (powderslurries).

Non limiting examples of suitable substrates are, for example, wood,textiles, paper, ceramics, glass, glass fibres, plastics such aspolyester, polyethylene terephthalate, polyolefins or cellulose acetate,especially in the form of films, and also metals such as Al, Cu, Ni, Fe,Zn, Mg or Co and GaAs, Si or SiO₂.

The coating composition may also be an ink composition. Thus, thesubstrate is printed with an ink composition to form an ink film on thesubstrate.

Preparation of the Coating

The components of the formulation and optionally further additives areapplied uniformly to a substrate by means of known coating techniques,for example by spin-coating, immersion, knife coating, curtain pouring,brush application or spraying, especially by electrostatic spraying andreverse-roll coating, and also by electrophoretic deposition. Thequantity applied (coat thickness) and the nature of the substrate (layersupport) are dependent on the desired field of application. The range ofcoat thicknesses generally comprises values from 0.1 μm to 1 mm for gelcoates and more than 1 mm for composites.

Use

The photocurable compositions according to the invention are suitablefor a variety of purposes, for example for overprint coatings, forinkjet inks, for printing inks, especially flexographic printing inks,for clearcoats, whitecoats or color-pigmented paint, for example forwood or metal, for powder coatings, as coating materials for substratesof all kinds, e.g. wood, textiles, paper, ceramics, glass, glass fibres,plastics, such as polyesters, polyethylene terephthalate, polyolefins orcellulose acetate, especially in the form of films, and also for metals,such as Al, Cu, Ni, Fe or Zn and GaAs, Si or SiO₂, to which a protectivecoating is to be applied or an image is to be applied by imagewiseexposure.

Examples of coatings for metal include the application of a finish tometal sheets and tubes, cans or bottle closures, and topcoats forapplications in the automobile industry.

Examples of the photocuring of paper coatings are the application of acolourless finish to labels or book covers.

The photopolymerisable compositions can furthermore be used asdaylight-curable paints for marking structures and roads, forphotographic reproduction techniques, for holographic recordingmaterials, for image recording processes or in the production ofprinting plates that can be developed using organic solvents or usingaqueous alkaline media, for the production of masks for screen printing,as dental filling compounds, as adhesives, as pressure-sensitiveadhesives, as laminating resins, as etch resists or permanent resists,both liquid and in the form of dry films, as photostructurabledielectrics, and as solder resists for electronic circuits, as resistsin the production of color filters for any type of display screen, or inthe creation of structures during the production of plasma displays andelectroluminescent displays, in the production of optical switches,optical gratings (interference gratings), in the production ofthree-dimensional articles by bulk curing (UV curing in transparentmoulds) or by the stereolithography process, as described, for example,in U.S. Pat. No. 4,575,330, in the production of composite materials(e.g. styrene polyesters which may, where appropriate, include glassfibres and/or other fibres and other adjuvants), and of fine layers (gelcoats) and thick-layered compositions, in the coating or sealing ofelectronic components, or as coatings for optical fibres. Thecompositions are suitable, furthermore, for the production of opticallenses, e.g. contact lenses or Fresnel lenses, and also for theproduction of medical instruments, aids or implants.

The compositions may also be used to produce gels having thermotropicproperties, such as are described, for example, in DE 197 00 064 and EP678 534.

A preferred area of use is in overprint coatings. Typically, theseconsist of ethylenically unsaturated compounds, such as oligomericand/or monomeric acrylates and aminoacrylates. Suitable compounds arelisted under “compound (A)”. The compounds and mixtures according to theinvention are especially effective in overprint coatings of small layerthickness (5-10 μm).

A further preferred area of use is in UV-curable flexographic printinginks. Such inks likewise consist of ethylenically unsaturated compounds(A) and comprise in addition UV flexographic resin/binder as well asfurther additives, such as flow agents and coloured pigments.

A further preferred area of use is in powder coatings. The powdercoatings may be based on solid resins and monomers containing reactivedouble bonds (compounds (A)), e.g. maleates, vinyl ethers, acrylates,acrylamides and mixtures thereof. The powder coatings may also comprisebinders, such as are described, for example, in DE 4 228 514 and EP 636669. The UV-curable powder coatings may also comprise white or colouredpigments.

A further preferred area of use is in inkjet inks.

Inkjet Inks Contain a Colorant

A wide variety of organic and inorganic dyes and pigments, alone or incombination, may be selected for use in the inkjet ink compositions ofthis invention. The pigment particles should be sufficiently small(0.005 to 15 μm) to permit free flow of the ink at the ejecting nozzles.The pigment particles should preferably be 0.005 to 1 μm.

Very fine dispersions of pigments and their preparation are disclosed ine.g. U.S. Pat. No. 5,538,548.

The pigment can be black, white, cyan, magenta, yellow, red, blue,green, brown, mixtures thereof, and the like. For example, suitablepigment materials include carbon blacks such as Regal 400R, Mogul L,Elftex 320 from Cabot Colo., or Carbon Black FW18, Special Black 250,Special Black 350, Special Black 550, Printex 25, Printex 35, Printex55, Printex 150T from Degussa Co., and Pigment Black 7. Additionalexamples of suitable pigments are disclosed in, for example, U.S. Pat.No. 5,389,133.

Suitable white pigments are titanium dioxide (modifications rutile andanatas), e.g. KRONOS 2063 from Kronos, or HOMBITAN R610 L fromSachtleben.

Suitable pigments include, for instance, C. I. Pigment Yellow 17, C. I.Pigment Blue 27, C. I. Pigment Red 49:2, C. I. Pigment Red 81:1, C. I.Pigment Red 81:3, C. I. Pigment Red 81:x, C. I. Pigment Yellow 83, C. I.Pigment Red 57:1, C. I. Pigment Red 49:1, C. I. Pigment Violet 23, C. I.Pigment Green 7, C. I. Pigment Blue 61, C. I. Pigment Red 48:1, C. I.Pigment Red 52:1, C. I. Pigment Violet 1, C. I. Pigment White 6, C. I.Pigment Blue 15, C. I. Pigment Yellow 12, C. I. Pigment Blue 56, C. I.Pigment Orange 5, C. I. Pigment Black 7, C. I. Pigment Yellow 14, C. I.Pigment Red 48:2, C. I. Pigment Blue 15:3, C. I. Pigment Yellow 1, C. I.Pigment Yellow 3, C. I. Pigment Yellow 13, C. I. Pigment Orange 16, C.I. Pigment Yellow 55, C. I. Pigment Red 41, C. I. Pigment Orange 34, C.I. Pigment Blue 62, C. I. Pigment Red 22, C. I. Pigment Red 170, C. I.Pigment Red 88, C. I. Pigment Yellow 151, C. I. Pigment Red 184, C. I.Pigment Blue 1:2, C. I. Pigment Red 3, C. I. Pigment Blue 15:1, C.I.Pigment Blue 15:3, C.I. Pigment Blue 15:4, C. I. Pigment Red 23, C. I.Pigment Red 112, C. I. Pigment Yellow 126, C. I. Pigment Red 169, C. I.Pigment Orange 13, C. I. Pigment Red 1-10, 12, C.I. Pigment Blue 1:X,C.I. Pigment Yellow 42, C.I. Pigment Red 101, C.I. Pigment Brown 6, C.I. Pigment Brown 7, C. I. Pigment Brown 7:X, C. I. Pigment Black 11, C.I. Pigment Metal 1, C. I. Pigment Metal 2, C.I. Pigment Yellow 128, C.I.Pigment Yellow 93, C.I. Pigment Yellow 74, C.I. Pigment Yellow 138, C.I.Pigment Yellow 139, C.I. Pigment Yellow 154, C. I. Pigment Yellow 185,C.I. Pigment Yellow 180, C.I. Pigment Red 122, C.I. Pigment Red 184, andbridged aluminum phtalocyanine pigments, C. I. Pigment Red 254, C. I.Pigment Red 255, C.I. Pigment Red 264, C. I. Pigment Red 270, C.I.Pigment Red 272, C. I. Pigment Violet 19, C.I. Pigment Red 166, C.I.Pigment Red 144C. I. Pigment Red 202, C. I. Pigment Yellow 110, C. I.Pigment Yellow 128, C. I. Pigment Yellow 150, C. I. Pigment Orange 71,C. I. Pigment Orange 64, C. I. Pigment Blue 60.

The pigment may, but need not, be in the form of a dispersion comprisinga dispersant, also called pigment stabilizer. The latter may be, forexample, of the polyester, polyurethane or polyacrylate type, especiallyin the form of a high molecular weight block copolymer, and wouldtypically be incorporated at 2.5% to 100% by weight of the pigment. Anexample of a polyurethane dispersant is EFKA 4047.

Further pigment dispersions are (UNISPERSE, IRGASPERSE) and ORASOL Dyes(solvent soluble dyes): C.I. Solvent Yellow 146, C.I. Solvent Yellow 88,C.I. Solvent Yellow 89, C.I. Solvent Yellow 25, C.I. Solvent Orange 11,C.I. Solvent Orange 99, C.I. Solvent Brown 42, C.I. Solvent Brown 43,C.I. Solvent Brown 44, C.I. Solvent Red 130, C.I. Solvent Red 233, C.I.Solvent Red 125, C.I. Solvent Red 122, C.I. Solvent Red 127, C.I.Solvent Blue 136, C.I. Solvent Blue 67, C.I. Solvent Blue 70, C.I.Solvent Black 28, C.I. Solvent Black 29

Especially emphazised are the MICROLITH-pigment preparationscommercially available from Ciba Specialty Chemicals Inc. These pigmentdispersions may be organic or inorganic pigments predispersed in avariety of resins, e.g. in vinyl resins, acrylic resins and aromaticpolyurethane resins. MICROLITH-WA may for example be a line of pigmentspredispersed in alkaline water/alcohol soluble acrylic resin (speciallydeveloped for aqueous gravure and flexographic printing) with pigmentsthat may be compatible with UV and inkjet printing inks.

The Microlith-K inkjet products are used in vinyl-based inks, which canbe formulated to give good adhesion to many substrates, from plasticizedand rigid PVC and metal foils, to polymer coated regenerated cellulosefilms.

Inkjet inks of the present invention may also more generally includeother pigment preparations such as chips or in situ combination duringgrinding of pigments (as described above) and hyperdispersants(e.g.Solsperse as available from Avecia) into the binder carrier.

The substrates can be coated by applying a liquid composition, asolution or suspension to the substrate. The choice of solvent and theconcentration are guided primarily by the nature of the composition andby the coating technique. The solvent should be inert, i.e. it shouldnot enter into any chemical reaction with the components and it shouldbe able to be removed again in the course of drying after coating.Examples of suitable solvents are ketones, ethers and esters, such asmethyl ethyl ketone, isobutyl methyl ketone, cyclo-pentanone,cyclohexanone, N-methylpyrrolidone, dioxane, tetrahydrofuran,2-methoxy-ethanol, 2-ethoxyethanol, 1-methoxy-2-propanol,1,2-dimethoxyethane, ethyl acetate, n-butyl acetate and ethyl3-ethoxypropionate.

The formulation is applied uniformly to a substrate by means of knowncoating techniques, for example by spincoating, dipping, knife coating,curtain coating techniques, brush application, spraying, especially byelectrostatic spraying, and reverse roll coating, and also byelectrophoretic deposition. It is also possible to apply thephotosensitive layer to a temporary flexible support and then totransfer the layer by lamination to the final substrate. Examples ofmethods of application can be found e.g. in Ullmann's Encyclopedia ofIndustrial Chemistry, 5^(th) edition, Vol. A18, pp. 491-500.

The amount applied (layer thickness) and the nature of the substrate(layer support) are dependent on the desired field of application. Therange of dry film thicknesses generally embraces values from about 0.1μm to more than 100 μm.

The photosensitivity of the compositions of the invention generallyranges from about 200 nm into the NIR or IR region.

NIR (Near Infrared)-Curing

The NIR radiation used in the process according to the invention isshort-wave infrared radiation in the wavelength range from about 750 nmto about 1500 nm, preferably 750 nm to 1200 nm. Radiation sources forNIR radiation include, for example, conventional NIR radiation emitters,which are available commercially (for example, from Adphos).

IR-Curing

The IR radiation used in the process according to the invention ismedium-wave radiation in the wavelength range from about 1500 nm toabout 3000 nm and/or longer-wave infra-red radiation in the wavelengthrange above 3000 nm.

IR radiation emitters of this kind are available commercially (forexample, from Heraeus).

UV-Curing

The photochemical curing step is carried out usually using light ofwavelengths from about 200 nm to about 600 nm, especially from 200 to450 nm. As light sources there are used a large number of the mostvaried types. Both point sources and planiform projectors (lamp carpets)are suitable. Examples are: carbon arc lamps, xenon arc lamps, medium-,high- and low-pressure mercury lamps, optionally doped with metalhalides (metal halide lamps), microwave-excited metal-vapor lamps,excimer lamps, super actinic fluorescent tubes, fluorescent lamps, argonfilament lamps, electronic flash lamps, photographic flood lights,electron beams light emitting diodes (LED) and X-rays generated by meansof synchrotrons or laser plasma.

As already mentioned, curing in the process of the invention may takeplace solely by exposure to electromagnetic radiation. Depending on thecomposition of the formulation to be cured, however, thermal curingbefore, during or after irradiation is advantageous.

Thermal curing takes place in accordance with methods known to theperson skilled in the art. Curing is generally carried out in an oven,e.g. a circulating air oven, on a hotplate, or by irradiation using IRlamps. Curing without aids at room temperature is likewise possible,depending on the binder system used. The curing temperatures aregenerally from room temperature to 150° C., e.g. 25-150° C. or 50-150°C. In the case of powder coatings or “coil coat” coatings, the curingtemperatures may also be higher, e.g. up to 350° C.

The invention relates also to a method of producing a scratch-resistantdurable surface, wherein a composition that either contains anethylenically unsaturated compound and a photoinitiator of formula 1, isapplied to a support; and curing of the formulation is carried outeither solely by irradiation with electromagnetic radiation of awavelength ranging from 200 nm into the NIR or IR region, or byirradiation with electromagnetic radiation and prior, simultaneousand/or subsequent action of heat.

The invention relates also to the use of the above-described compositionand to a process for the production of pigmented and unpigmented surfacecoatings, overprint coatings, formulations for printing inks, inkjetinks, powder coatings, fine layers (gel coats), composite materials orglass fibre cable coatings.

The invention further relates to the use of the compounds of formula Ito prepare multifunctional photoinitiators.

EXAMPLES Example 1 Synthesis of2-benzyl-1-[4-(2-hydroxyethylamino)phenyl]-2-dimethylamino-1-butanone

1.1: 2-Benzyl-1-(4-fluorophenyl)-2-dimethylamino-1-butanone

This compound is prepared according to the procedure in EP-0284561-A2(example 1 B).

1.2:2-Benzyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-butanone

44.9 g (0.15 mol) 2-Benzyl-1-(4-fluorophenyl)-2-dimethylamino-1-butanoneand 61.08 g (1.05 mol) ethanolamine are dissolved in 400 mldimethylacetamide. 41.5 (0.3 mol) Potassium carbonate are added and thesuspension is heated to 140° C. while stirring. The reaction mixture iskept at this temperature during 16 hours, cooled to room temperature anddiluted with water. The aqueous phase is several times extracted withethyl acetate, the combined organic extracts washed with water and driedover magnesium sulfate. Evaporation of the solvent gives the crudeproduct as a yellowish-brown oil. The product is purified bychromatography on silica gel (eluent: petroleum ether/ethyl acetate2:1→1:1). The fractions containing the product are collected to give aslightly yellowish solid product. Recrystallisation from ethylacetate/hexane gave2-benzyl-1-[4-(2-hydroxyethylamino)phenyl]-2-dimethylamino-1-butanone asslightly yellowish crystals melting at 109-111° C. Yield: 34.7 g (68%).¹H-NMR data are in agreement with the proposed structure.

Elemental analysis: C₂₁H₂₈N₂O₂ (MG=340.5)

C % H % N % calculated: 74.08 8.29 8.23 found: 73.95 8.42 7.99

Example 2 Synthesis of2-[(4-aminophenyl)methyl]-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-butanone

2.1:2-[(4-Nitrophenyl)methyl]-1-(4-fluorophenyl)-2-dimethylamino-1-butanone

2-Benzyl-1-(4-fluorophenyl)-2-dimethylamino-1-butanone, obtained asdescribed for example 1.1, is added dropwise at 0-5° C. to fuming nitricacid: After the addition, the reaction mixture is stirred for one hourand subsequently poured onto ice/water. The solution is extractedseveral times with methyl ethyl ketone, the organic extracts dried overmagnesium sulfate and the solvent evaporated. The crude product is thusobtained as a brownish oil, which is purified by flash chromatography onsilica gel using petroleum ether/ethyl acetate 4:1 as eluent.2-[(4-Nitrophenyl)methyl]-1-(4-fluorophenyl)-2-dimethylamino-1-butanoneis obtained as a yellowish oil that is used for the next step withoutfurther purification.

2.2:2-[(4-Aminophenyl)methyl]-1-(4-fluorophenyl)-2-dimethylamino-1-butanone

7.0 g Palladium on charcoal (5%) are added to solution of 69.5 g (0.178mol)2-[(4-nitro-phenyl)methyl]-1-(4-fluorophenyl)-2-dimethylamino-1-butanonein 700 ml ethanol in an hydrogenation autoclave. Hydrogen is enteredwith a continuous increase of pressure to 5 bar at temperature betweenroom temperature and 40° C. After 25 hours no further hydrogen uptake isobserved. The catalyst is filtered off and the crude product obtained asyellowish oil after evaporation of the solvent. Thin film chromatographyshows a main product and some minor by-products. The crude material isused without further purification in the next reaction step.

2.3:2-[(4-aminophenyl)methyl]-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-butan-one

23.5 g (0.078 mol)2-[(4-aminophenyl)methyl]-1-(4-fluorophenyl)-2-dimethylamino-1-butanoneare reacted with ethanol amine (33.4 g, 0.55 mol) under conditions asdescribed for example 1.2. The crude product obtained is purified byfirst by filtration over silica gel using hexane/ethyl acetate 1:1→ethylacetate as the eluent, followed by flash chromatography on silica gel(eluant: ethyl acetate). 10.2 g (37%)2-[(4-aminophenyl)methyl]-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-butanoneare obtained as a viscous yellow oil.

¹H NMR (ppm; TMS=0 ppm as internal standard); 8.3 (d, 2H—C(2′)/C(6′));7.0 (d, 2H—C(2″′) and C(6″′)); 6.62 (d, 2H—C(3″′) and C(5″′)); 6.53 (d,2H—C(3′)/C(5′)); 3.83 (t, 2H—C(8′)); 3.33 (t, 2H—C(7′)); 3.07 (broad s,2NH); 2.95 (d, 2H—C(1″′)); 2.36 (s, 6H (CH₃—N)); 2.02 (m, 1H—(C(1″);1.81 (m, 1H—(C(1″); 0.71 (t, 3H—C(2″).

Elemental analysis: C₂₁H₂₉N₃O₂ (MG=355.48)

C % H % N % calculated: 70.95 8.22 11.82 found: 69.11 8.51 11.22

Example 3 Synthesis of2-ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-pent-4-en-1-one

3.1: 1-(4-Fluorophenyl)-2-dimethylamino-1-butanone

This compound is prepared according to the procedure in EP-02845610-A2(example 1 A).

3.2. 2-Ethyl-1-(4-fluorophenyl)-2-dimethylamino-pent-4-en-1-one

76 g (0.363 mol) 1-(4-Fluorophenyl)-2-dimethylamino-1-butanone aredissolved in 300 ml methyl ethyl ketone. While stirring at roomtemperature, 48.3 g (0.4 mol) 1-bromo-prop-2-ene are added over one hourto give a beige suspension. The reaction mixture is stirred for 18 hoursat room temperature and then heated to 70° C. At this temperature 29.05g (0.73 mol) powdered sodium hydroxide are added. The reaction mixtureturns orange and is subsequently cooled to room temperature. The mixtureis diluted with water and dichloro-methane. The organic phase isseparated, dried over magnesium sulfate and the solvent evaporated. Thecrude product thus obtained is purified by flash chromatography onsilica gel, using petroleum ether/ethyl acetate as the eluent.2-Ethyl-1-(4-fluorophenyl)-2-dimethyl-amino-pent-4-en-1-one is obtainedas a yellowish liquid. Yield: 56.9 g (63%). ¹H-NMR data are in agreementwith the proposed structure.

3.3:2-Ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-pent-4-en-1-one

24.9 g (0.1 mol)2-Ethyl-1-(4-fluorophenyl)-2-dimethylamino-pent-4-en-1-one are reactedwith ethanol amine under conditions as described for example 1.2. Thecrude product is obtained as yellowish liquid, which is further,purified by chromatography on silica gel using petroleum ether/ethylacetate as eluent. The fractions containing the product are collectedand the compound recrystallized from hexane.2-Allyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethyl-amino-1-butanone(16.2 g, 56%) is obtained as slightly yellowish crystals with a meltingpoint of 90-92° C. %). ¹H-NMR data are in agreement with the proposedstructure.

¹H NMR (ppm; TMS=0 ppm as internal standard); 8.3 (d, 2H—C(2′)/C(6′));6.54 (d, 2H—C(3′)/C(5′)); 5.94 (m, H—C(4)); 5.07 (dxd, 1 H—C(5); 4.98(dxd, 1 H—C(5)); 3.87 (t, 2H—C(8′); 3.37 (t, 2H—C(7′)); 2.7-2.5 (m,2H—C(3)); 2.44 (s, 6H (CH₃—N)); 2.15-1.8 (m, 3H, 2H—(C(1″) and OH); 0.73(t, 3H—C(2″).

Example 4 Synthesis of1-[4-(2-hydroxyethyamino)phenyl]-2-methyl-2-dimethylamino-1-pent-4-en-1-one

This compounds is prepared by the same procedure as Example 2, exceptthat 1-(4-fluorophenyl)-2-dimethylamino-1-propanone is used as thestarting material.

¹H NMR (ppm; TMS=0 ppm as internal standard); 8.43 (d, 2H—C(2′)/C(6′));6.54 (d, 2H—C(3′)/C(5′)); 5.54 (m, H—C(4)); 4.90 (dxd, 1 H—C(5); 4.87(dxd, 1H—C(5)); 3.87 (t, 2H—C(8′); 3.37 (t, 2H—C(7′)); 2.75 (dxd,1H—C(3)); 2.40 (dxd. 1H—C(3)); 2.26 (s, 6H (CH₃—N)); 1.74 (broad s, OH);1.17 (s, 3H—C(1″).

Example 5 Synthesis of2-ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-(morpholin-4-yl)-1-pent-4-en-1-one

5.1 1-(4-Fluorophenyl)-2-(morpholin-4-yl)-1-butanone

85.3 g (0.98 mol) morpholine are dissolved in 200 ml tetrahydrofuraneand cooled to 0° C. 100 g (0.41 mol)1-(4-Fluorophenyl)-2-bromo-1-butanone (obtained according to the processdescribed in EP-A-3002) in 200 ml tetrahydrofurane are added dropwise tothis solution at 0° C. The reaction mixture is then heated to 50° C.during 16 hours before cooling to room temperature. The mixture ispoured into water and extracted several times with ethyl acetate. Theorganic phase is dried with magnesium sulfate and the solvent evaporatedin vacuo. 1-(4-Fluorophenyl)-2-(morpholin-4-yl)-1-butanone (102 g, 99%)is thus obtained as a brownish liquid, the structure being confirmed by¹H-NMR analysis. The crude product is used without further purificationfor the next reaction step.

5.2 2-Ethyl-1-(4-fluorophenyl)-2-(morpholin-4-yl)-pent4-en-1-one

56 g of a 50% suspension of sodium hydride in mineral oil (0.22 molsodium hydride) is added to 100 ml dimethylformamide. 45.2 g (0.16 mol)1-(4-Fluorophenyl)-2-(morpholin-4-yl)-1-butanone, dissolved in 50 mldiemethylformamide, are added to this suspension dropwise and at roomtemperature, and subsequently stirred overnight. Then, 19.36 g1-brom-2-propene are added dropwise. The temperature raises to 50° C.and the solution is kept at this temperature for 16 hours. Aftercooling, excess sodium hydride is destroyed by the addition of 5 mlisopropanol and the reaction mixture subsequently poured onto anice/water mixture. The organic products are extracted with ethylacetate, the combined extracts dried over magnesium sulfate and thesolvent evaporated. The crude product thus obtained is purified bychromatography silica gel (eluent: ethyl acetate/petroleum ether 4:1).2-Ethyl-1-(4-fluoro-phenyl)-2-(morpholin-4-yl)-pent-4-en-1-one (17.8 g,38%) is obtained as a yellowish oil. ¹H-NMR analysis is in agreementwith the proposed structure. This compound is used for the next step.

5.3.2-Ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-(morpholin-4-yl)-1-pent-4-en-1-one

11.4 g (0.04 mol)2-Ethyl-1-(4-fluorophenyl)-2-(morpholin-4-yl)-pent-4-en-1-one arereacted with 17.1 g (0.28 mol) ethanolamine under conditions asdescribed for example 1.2. The crude product is purified bychromatography on silica gel using petroleum ether/ethyl acetate 2:3 aseluent. Pure2-ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-(morpholin-4-yl)-1-pent4-en-1-one(3.6 g, 27%) is obtained as a yellowish viscous oil.

¹H NMR (ppm; TMS=0 ppm as internal standard); 8.41 (d, 2H—C(2′)/C(6′));6.52 (d, 2H—C(3′)/C(5′)); 5.92 (m, H—C(4)); 5.08 (dxd, 1 H—C(5); 5.02(dxd, 1H—C(5)); 4.77 (broad s, OH); 3.84 (t, 2H—C(8′); 3.62 (7.4H—C(2″′)and C(6″′); 3.34 (broad t, 2H—C(7′)); 2.9-2.85 (m, 2H—C(3)); 2.25-2.10(m, 4H—C(3″4 ) and C(5″′); 2.10-1.85 (m, 2H—C(1″)); 0.72 (t, 3H_C(2″)).

Elemental analysis: C₁₉H₂₈N₂O₅ (MG=332.44)

C % H % N % calculated: 68.65 8.49 8.43 found: 68.32 8.58 8.37

Example 6 Synthesis of1-[4-(2-hydroxyethyamino)phenyl]-2-methyl-2-(morpholin-4-yl)-1-propanone

9.6 g (0.03 mol) 1-(4-fluorophenyl)-2-(morpholin-4-yl)-1-propanone(prepared as described in DE 19753655-A1, example 1b) are reacted with12.85 g (0.21 mol) ethanolamine under conditions as described forexample 1.2. The crude product is purified by chromatography on silicagel using petroleum ether/ethyl acetate 1:2 as eluent. The fractionscontaining the product are collected and the brownish crystalsrecrystallized from hexane/ethyl acetate 4:1. Pure1-[4-(2-hydroxyethyamino)phenyl]-2-methyl-2-(morpholin-4-yl)-1-propanone(5.1 g, 58%) is obtained as beige crystals with a melting point of77-78° C.

Elemental analysis: C₁₆H₂₄N₂O₃ (MG=292.4)

C % H % N % calculated: 65.73 8.27 9.58 found: 65.82 8.31 9.72

Example 7 Synthesis of2-ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-pentan-1-one

10.1 g2-Allyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-butanone aredissolved in 100 ml ethyl acetate. After addition of 1 g Pd/carbon 5%,the reaction mixture is treated with hydrogen at normal pressure untilan uptake of 0.78 1 H₂ (100%) is reached. After filtration of thecatalyst the solvent is evaporated. The crude product is recrystallizedfrom hexane to give 6.8 g (67%)2-ethyl-1-[4-(2-hydroxyethyamino)phenyl]-2-dimethylamino-1-pentan-1-oneas a slightly yellowish solid with a melting point of 74-77° C.

Elemental analysis: C₁₇H₂₈N₂O₂ (MG=292.4)

C % H % N % calculated: 69.83 9.65 9.58 found: 69.99 9.52 9.53

Example 8 Synthesis of2-Benzyl-2-dimethylamino-1-{[4-(2-acetoxyethyl-2-hydroxyethyl-amino)-phenyl}-1-butanone

8.1: 1-{[4-[Bis(2-hydroxyethyl)amino]phenyl}-1-butanone

49.5 g (0.3 mol) 1-(4-Fluorophenyl)-1-butanon and 315.4 g (3.0 mol) areheated in a steel autoclave under a pressure of 8-10 bar to 200° C.during 100 hours. After cooling the reaction mixture is poured onice/water, the organic phase is separated and the water phase extractedseveral times with ethyl acetate. The organic extracts are dried overmagnesium sulfate and the solvent evaporated. The brownish crude productis filtered over silica gel using ethyl acetate/petroleum ether aseluent. 1-{[4-[Bis(2-hydroxyethy)amino]phenyl}-1-butanone is obtained asa solid which is recrystallized in ethyl acetate/hexane 7:2 to give theproduct as a beige solid with a melting point of 72-75° C.

8.2: 1-{[4-[Bis(2-acetoxyethyl)amino]phenyl}-2-bromo-1-butanone

34.9 g (0.138 mol) 1-{[4-[Bis(2-hydroxyethy)amino]phenyl}-1-butanone aredissolved in 500 ml acetic acid. The solution is saturated with gaseoushydrogen chloride and subsequently cooled to 0-5° C. 22.2 g (0.138 mol)bromine are added at this temperature over 90 minutes. The reactionmixture is subsequently stirred over night at room temperature. Afterheating under a stream of nitrogen, the reaction mixture is pouredslowly into 550 ml of 30% sodium hydroxide solution. Extraction withethyl acetate, followed by drying over magnesium sulfate and evaporationof the solvent gives 55 g1-{[4-[bis(2-acetoxyethyl)amino]phenyl}-2-bromo-1-butanone as a brownishliquid.

¹H NMR (ppm; TMS=0 ppm as internal standard); 7.91 (d, 2H—C(2′)/C(6′));6.77 (d, 2H—C(3′)/C(5′)); 5.05 (t, H—C(2)); 4.27 (t, 42H—C(2″)); 3.69(t, 4H—C(1″)); 2.16 (txd, 2H—C(3)); 2.05 (s. 6H CH₃CO); 1.05 (t,3H—C(4)).

8.3: 2-Dimethylamino-1-{[4-[bis(2-acetoxyethyl)amino]phenyl}-1-butanone

25 g (0.06 mol)1-{[4-[bis(2-acetoxyethyl)amino]phenyl}2-bromo-1-butanone are addeddropwise to 25 g of a 33% solution of dimethylamine in ethanol (0.18 moldimethylamine) at 0° C. The reaction mixture is stirred over night atroom temperature, after which the solvent subsequently is evaporated invacuum. 20.0 g (88%)2-Dimethylamino-1-{[4-[bis(2-acetoxy-ethyl)amino]phenyl}-1-butanone areobtained as a yellowish liquid which is used in the next reaction stepwithout further purification.

¹H NMR (ppm; TMS=0 ppm as internal standard); 7.98 (d, 2H—C(2′)/C(6′));6.77 (d, 2H—C(3′)/C(5′)); 4.27 (t, 4H—C(2″)); 3.80 (m, H—C(2)); 3.71 (t,4H—C(1″)); 2.32 (s, 6H CH₃—N); 2.05 (s. 6H CH₃CO); 1.72 (txd, 2H—C(3));0.85 (t, 3H—C(4)).

8.4.:2-Benzyl-2-dimethylamino-1-{[4-[bis(2-acetoxyethyl)amino]phenyl}-1-butanone

To a solution of 12.5 g2-dimethylamino-1-{[4-[bis(2-acetoxyethyl)amino]phenyl}-1-butanone in 25ml methyl ethyl ketone, 5.64 g (0.033 mol) benzyl bromide are addeddropwise. The reaction mixture is heated to 70° C. during four hours.Then, 2.64 g (0.066 mol) powdered sodium hydroxide are added and themixture heated for another two hours. After cooling, the reactionmixture is diluted with water and ethyl acetate. The organic phase isseparated, dried over magnesium sulfate and the solvent evaporated togive a yellowish viscous liquid. This crude reaction mixture is purifiedby chromatography on silica gel using petroleum ether/ethyl acetate 1:1as the eluent. A first fraction isolated consists of 8.4 g2-Benzyl-2-dimethylamino-1-{[4-[bis(2-acetoxyethyl)amino]phenyl}-1-butanone,obtained as a yellowish oil.

Elemental analysis: C₂₇H₃₆N₂O₅ (MG=468.59)

C % H % N % calculated: 69.21 7.74 5.98 found: 69.40 8.13 5.49

8.5.:2-Benzyl-2-dimethylamino-1-{[4-(2-acetoxyethyl-2-hydroxyethyl-amino)-phenyl}-1-butanone

A second fraction from the chromatography described under 8.4 contains3.4 g2-benzyl-2-dimethylamino-1-{[4-(2-acetoxyethyl-2-hydroxyethyl-amino)-phenyl}-1-butanoneas a yellowish oil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.34 (d, 2H—C(2′)/C(6′));7.21 (m. 5H, benzylic protons); 6.68 (d, 2H—C(3′)/C(5′)); 4.31 (t,2H—C(2″)—OCOCH₃); 3.84 (t, 2H—C(2″)—OH); 3.70 (t, 2H—C(1″)—CH₂OCOCH₃);3.61 (t, 2H—C(1″)—CH₂OH); 3.18 (dxd, 2H—C(1′); 2.34 (s, 6H CH₃—N); 2.02(s. 3H CH₃CO); 2.05 and 1.85 (m, 2H—C(3)); 0.68 (t, 3H'C(4)).

Example 9 Synthesis of2-benzyl-1-{[4-[bis(2-hydroxyethy)amino]phenyl}-2-dimethylamino-1-butanone

3.4 g (0.008 mol)2-Benzyl-2-dimethylamino-1-{[4-(2-acetoxyethyl-2-hydroxyethyl-amino)-phenyl}-1-butanone,obtained according to example 8.5, are suspended in water and treatedwith powdered sodium hydroxide at 70° C. and then at reflux. After fivehours, the reaction mixture is cooled to room temperature and extractedwith ethyl acetate. The organic solution is dried over magnesium sulfateand the solvent evaporated. 1.7 g (55%)2-benzyl-1-{[4-[bis(2-hydroxyethy)amino]phenyl}-2-dimethylamino-1-butanoneare obtained as yellowish oil after chromatography on silicagel usingpetroleum ether/ethyl acetate as eluent.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.33 (d, 2H—C(2′)/C(6′));7.21 (m. 5H, benzylic protons); 6.59 (d, 2H—C(3′)/C(5′)); 3.88 (t,4H—C(2″)); 3.64 (t, 4H—C(1″)); 3.18 (dxd, 2H—C(1′); 2.34 (s, 6H CH₃—N);2.05 and 1.85 (m, 2H—C(3)); 0.68 (t, 3H—C(4)).

Elemental analysis: C₂₃H₃₂N₂O₃ (MG=384.52)

C % H % N % calculated: 71.84 8.39 7.29 found: 71.11 8.54 6.91

Example 10 Synthesis of2-dimethylamino-1-{[4-(2-acetoxyethyl-2-hydroxyethyl-amino)-phenyl}-2-ethyl-1-pent-4-en-1-one

This compound is prepared analogous to the procedure described forexample 8, except that allyl bromide is used instead of benzyl bromidein step 8.4. The compound is obtained as a yellowish viscous oil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.34 (d, 2H—C(2′)/C(6′));6.67 (d, 2H—C(3′)/C(5′)); 5.94 (m, 1H, H—C(4)); 5.06 (dxd, 1H H—C(5));4.99 (dxd, 1H, H—C(5)); 4.30 (t, 2H—C(2″)—OCOCH₃); 3.84 (t,2H—C(2″)—OH); 3.71 (t, 2H—C(1″)—CH₂OCOCH₃); 3.61 (t, 2H—C(1″)—CH₂OH);2.64 (m, 2H—C(3); 2.41 (s, 6H CH₃—N); 2.04 (s. 3H CH₃CO); 2.05 and 1.85(m, 2H—C(1′)); 0.68 (t, 3H—C(2′)).

Elemental analysis: C₂₁H₃₂N₂O₄ (MG=376.50)

C % H % N % calculated: 66.99 8.57 7.44 found: 66.63 8.56 6.86

Example 11 Synthesis of2-dimethylamino-1-{[4-[bis(2-hydroxyethy)amino]-phenyl}-2-ethyl-1-pent-4-en-1-one

This compound is prepared analogous to the procedure described forexample 9, except that the compound of example 10 is used as startingmaterial. The compound is obtained as a yellowish viscous oil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.33 (d, 2H—C(2′)/C(6′));6.57 (d, 2H—C(3′)/C(5′)); 5.90 (m, 1H, H—C(4)); 5.06 (dxd, 1H H—C(5));4.99 (dxd, 1H, H—C(5)); 3.85 (t, 4H—C(2″)); 3.62 (t, 4H—C(1″)); 2.64 (m,2H—C(3); 2.40 (s, 6H CH₃—N); 2.02 and 1.86 (m, 2H—C(1′)); 0.70 (t,3H—C(2′)).

Elemental analysis: C₁₉H₃₀N₂O₃ (MG=334.46)

C % H % N % calculated: 68.23 9.04 8.38 found: 67.63 9.33 7.80

Example 12 Synthesis of2-dimethylamino-1-{[4-[bis(2-hydroxyethy)amino]-phenyl}-2-ethyl-1-pentan-1-one

This compound is prepared analogous to the procedure described forexample 7, except that the compound of example 11 is used as startingmaterial for the hydrogenation. The compound is obtained as a yellowishviscous oil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.29 (d, 2H—C(2′)/C(6′));6.57 (d, 2H—C(3′)/C(5′); 3.85 (t, 4H—C(2″)); 3.62 (t, 4H—C(1″)); 2.40(s, 6H CH₃—N); 1.85 (m, 4H, 2H—C(3) and 2H—C(1′)); 1.15 (m, 2H—C(4));0.85 (t, 3H—C(5)); 0.78 (t, 3H—C(2′)).

Elemental analysis: C₁₉H₃₂N₂O₃ (MG=336.47)

C % H % N % calculated: 67.82 9.59 8.33 found: 66.85 9.54 7.75

Example 13 Synthesis of Synthesis of1-{[4-[bis(2-hydroxyethy)amino]-phenyl}-2-ethyl-2-morpholin-4-yl)-1-pent-4-en-1-one

This compound is prepared analogous to the procedure described forexample 11, except that in the amination step morpholine is used instead of dimethylamine. The compound is obtained as a yellowish viscousoil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 7.98 (d, 2H—C(2′)/C(6′));6.68 (d, 2H—C(3′)/C(5′)); 5.85 (m, 1H, H—C(4)); 5.25 (dxd, 1H H—C(5));5.18 (dxd, 1H, H—C(5)); 4.0-3.55 (4 m, 14H, 4H—C(2″), 4H—C(1″),4H—C(2″′/6″′) and 2H—C(3)); 2.60 (m, 4H—C(3″′/5″′)); 1.90 and 1.75 (m,2H—C(1′)); 0.85 (t, 3H—C(2′)).

Elemental analysis: C₂₁H₃₂N₂O₄ (MG=376.47)

C % H % N % calculated: 66.99 8.57 7.44 found: 66.78 8.62 7.24

Example 14 Synthesis of2-benzyl-1-{4-[(2-hydroxyethyl)-acryloyl-amino]phenyl}-2-dimethylamino-1-butanone

6.0 g (0.018 mol)2-Benzyl-1-[4-(2-hydroxyethylamino)phenyl]-2-dimethylamino-1-butanone(example 1) is dissolved in 50 ml methyl ethyl ketone and cooled to 0-5°C. A solution of 1.4 g sodium hydroxide in 5 ml water is added, followedby the dropwise addition of 1.8 g acryloyl chloride. When the additionis complete, the reaction mixture is stirred for an additional 10minutes and poured in water. The organic phase is separated, dried overmagnesium sulfate and the solvent evaporated in vacuo. The brownish oilobtained is purified by chromatography on silica gel, using petroleumether/ethyl acetate as eluent. A first fraction (2.0 g) conconsistsaccording to ¹H-NMR-analysis of 60%2-benzyl-1-{4-[(2-acryloyloxyethyl)-amino]phenyl}2-dimethylamino-1-butanoneand 40%2-benzyl-1-{4-[(2-acryloyloxyethyl)-acryloyl-amino]phenyl}-2-dimethylamino-1-butanone.

A second fraction (2.0 g) is pure2-benzyl-1-{4-[(2-hydroxyethyl)-acryloyl-amino]phenyl}-2-dimethylamino-1-butanone.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.38 (d, 2H—C(2′)/C(6′));7.3-7.1 (m, 2H—C(3′)/C(5′) and 5 benzylic protons); 6.42 (dxd, 1H,H—C(3″′)); 6.05 (dxd, 1H H—C(3″′)); 5.61 (dxd,1H, H—C(2″′)); 4.0 (t,2H—C(2″)); 3.82 (t, 2H—C(1″); 3.20 (m, 2H—C(1′)); 2.38 (s, 6H, CH3—N);2.10 and 1.82 (m, 2H—C(3)); 0.71 (t, 3H—C(4)). The IR spectrum (KBr)shows an amide band at 1670 cm⁻¹.

Elemental analysis: C₂₄H₃₀N₂O₃ (MG=394.52)

C % H % N % calculated: 73.07 7.67 7.10 found: 73.60 8.45 6.26

Example 15 Synthesis of2-Dimethylamino-2-ethyl-1-{4-[(2-hydroxy-ethyl)-methyl-amino]-phenyl}-pent-4-en-1-one

In a 300 ml sulfonation under argon atmosphere, 2.90 g (10 mmol) of2-dimethylamino-2-ethyl-1-[4-(2-hydroxy-ethylamino)-phenyl]-pent-4-en-1-oneare dissolved in 55 ml THF and 137 ml acetonitrile. 4.5 ml (60 mmol) ofa 37% aqueous formaldehyde solution are added over 10 min. at 25° C.,followed by 2.21 g (30 mmol) of sodium cyanoborohydride. After 10 min at25° C., the mixture is stirred at 50° C. for 4 h, cooled to roomtemperature and diluted with 100 ml water. The yellow semi-solid isredissolved in methylene chloride, washed with 20 ml of aq. sat. NaHCO₃and water, the organic phase dried with brine and sodium sulfate, andevaporated under vacuum to give 2.3 g (75%) of the title compound as ayellow oil.

¹H-NMR (CDCl₃, 400 MHz); [ppm]: 8.30 (d, 2H),6.66 (d, 2H), 5.85-5.96 (m,1H), 5.01-5.11 (m, 2H), 3.85 (t, 2H), 3.58 (t, 2H), 3.08 (s, 3H),2.64-2.75 (m, 2H), 2.47 (s, 6H), 1.91-2.07 (m, 2H), 0.73 (t, 3H).

Example 16 Synthesis of2,8-diallyl-2,8-bis-dimethylamino-1.9-bis-[4-(2-hydroxy-ethylamino)-phenyl]-nonane-1,9-dione

16.1.: 1.9-Bis-(4-fluoro-phenyl)-nonane-1,9-dione

To a suspension of 32.0 g AlCl₃ in 290 ml fluorobenzene, 25 g azealicacid dichloride is added at 0-10° C. while stirring. The reactionmixture was stirred over night and subsequently hydrolysed with dilutehydrogen chloride. After extraction with dichloromethane, drying overmagnesium sulfate and evaporation of the solvent, 37.4 g1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione are obtained as a yellowishliquid.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.00 (m, 2H—C(2′)/C(6′));7.15 (m, 2H—C(3′)/C(5′)); 2.94 (t, 4H—C(2) and C(8)); 1.73 (m, 4H—C(3)and C(7)); 1.40 (m, 6H—C(4), C(5) and C(6)).

16.2.: 2,8-Dibromo-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione

37.4 g (0.11 mol) 1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione arebrominated with 35.16 g (0.22 mol) bromine under conditions analogous tothose described in example 8.2. 57.9 g2,8-Dibromo-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione are obtained,which are used for the next reaction step without further purification.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.07 (m, 2H—C(2′)/C(6′));7.20 (m, 2H—C(3′)/C(5′)); 5.06 (t, 2H—C(2) and C(8)); 2.18 (m, 4H—C(3)and C(7)); 1.51 (m, 6H—C(4), C(5) and C(6)).

16.3.: 2,8-dimethylamino-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione

30.2 g 2,8-Dibromo-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione arereacted with 5.6 mol dimethylamine under the conditions described forexample 8.3. 23.9 g2,8-dimethylamino-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione areobtained as yellowish viscous oil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.09 (m, 2H—C(2′)/C(6′));7.08 (m, 2H—C(3′)/C(5′)); 3.82 (m, 2H—C(2) and C(8)); 2.29 (6H, CH₃—N);1.8 and 1.6 (2 m, 4H—C(3) and C(7)); 1.35-1.10 (m, 6H—C(4), C(5) andC(6)).

16.4.:2,8-Diallyl-2,8-dimethylamino-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione

12.9 g 2,8-Dimethylamino-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dione (30mmol) are reacted with 7.98 g (66 mmol) allyl bromide under theconditions described for example 3.2. 8.66 g (57%)2,8-Diallyl-2,8-dimethylamino-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dioneare obtained as a viscous yellowish oil, which is purified bychromatography on silica gel (eluent: hexane/ethyl acetate 9:1.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.36 (m, 2H—C(2′)/C(6′));7.00 (m, 2H—C(3′)/C(5′)); 5.82 (m, 2H—C(2′/2″)); 4.99 (dxd,2H—C(3′/3″)); 4.96 (d, 2H—C(3′/3″)); 2.55 (m, 2H—C(2) and C(8)); 2.36(6H, CH₃—N); 1.8 and 1.65 (2 m, 4H—C(3) and C(7)); 1.15-0.75 (m,6H—C(4), C(5) and C(6)).

16.5.:2,8-Diallyl-2,8-bis-dimethylamino-1.9-bis-[4-(2-hydroxy-ethylamino)-phenyl]-nonane-1,9-dione

9.16 g Ethanolamine (0.15 mol) are reacted with 5.7 g (0.01 mol)2,8-diallyl-2,8-dimethyl-amino-1.9-bis-(4-fluoro-phenyl)-nonane-1,9-dionein dimethylacetamide under the conditions described for example 1.2.After isolation, the crude product is purified by chromatography onsilica gel using isopropanole/dichloromethane and thenethanol/dichloromethane as the eluent. 3.8 g (64%)2,8-Diallyl-2,8-bis-dimethylamino-1.9-bis-[4-(2-hydroxy-ethylamino)-phenyl]-nonane-1,9-dioneare obtained as a very viscous yellowish oil.

¹H-NMR (ppm; TMS=0 ppm as internal standard); 8.26 (d, 2H—C(2′)/C(6′));6.51 (d, 2H—C(3′)/C(5′)); 5.88 (m, 2H—C(2′/2″)); 4.99 (dxd,2H—C(3′/3″)); 4.95 (d, 2H—C(3′/3″)); 3.85 (m, 4H, 2H—C(2″) and2H—C(2″′)); 3.36 (m, 4H, 2H—C(1″) and 2H—C(1″′)); 2.55 (m, 2H—C(2) andC(8)); 2.35 (6H, CH₃—N); 2.0-1.65 (m, 4H—C(3) and C(7)); 1.205-0.70 (m,6H—C(4), C(5) and C(6)).

Example 17 Synthesis of2,5-diallyl-2,5-bis-dimethylamino-1.6-bis-[4-(2-hydroxy-ethylamino)-phenyl]-hexan-1,6-dione

This compound is prepared following the process described for example15. except that adipoyl dichloride is used in step 15.1. instead ofazealic The compound is obtained as a yellowish solid with a meltingpoint of 95-96° C.

Example 18 Synthesis of2,5-dibenzyl-2,5-bis-dimethylamino-1.6-bis-[4-(2-hydroxy-ethylamino)-phenyl]-hexan-1,6-dione

This compound is prepared following the process described for example16. except that benzyl bromide instead of allyl bromide.

The compound is obtained as a yellowish solid with a melting point of126-127° C.

Application Example Example 19 Curing of a Blue Offset Printing Ink onWhite Paper

A photocurable blue offset printing ink is preapared in accordance withthe following formulation:

18.3 g of Ebecryl® 1608 (UCB, Belgium)

18.3 g of Ebecryl® 657 (polyester acrylate from UCB, Belgium)

20.0 g of Ebecryl® 220 (urethane acrylate from UCB, Belgium)

20.9 g of Ebecryl® 150 (bisphenol A derivative diacrylate from UCB,Belgium)

22.5 g Irgalit blue GLO (Cu-phthalocyanine pigment from Ciba SpecialtyChemicals)

The above components are grounded down to a stock paste. Portions of thestock paste are mixed with the photoinitiators indicated in the table (%by weight on the stock paste). The solubility-of the-initiator in theformulation is rated as good (+), acceptable (±) or bad (−) and theresults shown in Table 1.

The blue printing ink thus obtained is applied with 1.5 g/m² (˜1.5 μmthickness) on white paper using a Prüfbau laboratory printing equipment.The samples are exposed in an irradiation apparatus with a 80 W/cmmercury lamp (IST). The rate of passage of the sample through theirradiation apparatus is thereby increased continuously until adequatecuring no longer occurs. The maximum rate at which the ink still passesthe properties test for surface cure and through cure is shown inTable 1. The odor of the cured film is rated on a scale from 1(odorless) to 3 (strong odor).

curing rate curing rate conc (m/min) for (m/min) for photoinitiator (%)solubility surface cure through cure odor Compound of 3.0 + 100 120 1example 1 4.0 + 140 170 1 Irgacure 369 3.0 − 70 110 1 4.0 − 90 130 1Irgacure 907 4.0 + 80 90 2-3

The results show that the compound of example 1 is more efficient as aphotoinitiator than the reference compounds while being equal or bettersoluble and odorless.

Example 20 Curing of a Blue Flexo Printing Ink on a White PolyethyleneFoil

A photocurable blue flexo printing ink is prepared in accordance withthe following formulation:

26.9 g of IRR 440 (flexo basic resin)

19.0 g of OTA 480 (acrylated trifunctional resin, UCB, Belgium)

18.0 g of Ebecryl® 645 (modified diacrylate of Bisphenol A epoxy resindiluted with 25% of TPGDA, from UCB, Belgium)

13.0 g of HDDA (1,6-hexanediol diacrylate)

10.0 g of Ebecryl® 220 (urethane acrylate from UCB, Belgium)

1.3 g of Ebecryl® 168 (methacrylated acidic compound from UCB, Belgium)

0.7 g of DC 57 (Leveling agent)

11.1 g Irgalit blue GLO (Cu-phthalocyanine pigment from Ciba SpecialtyChemicals)

The above components are grounded down to a stock paste. Portions of thestock paste are mixed with the photoinitiators indicated in the table (%by weight on the stock paste). The solubility of the initiator in theformulation is rated as good (+), acceptable (±) or bad (−) and theresults shown in Table 2.

The blue printing ink thus obtained is applied with 1.38 g/cm² 1.5 μmthickness on a corona treated white polyethylene foil using a Prüfbaulaboratory printing equipment. The samples are exposed in an irradiationapparatus with a 120 W/cm mercury lamp (IST). The rate of passage of thesample through the irradiation apparatus is thereby increasedcontinuously until adequate curing no longer occurs. The maximum rate atwhich the ink still passes the properties test for surface cure andthrough cure is shown in Table 1. The adhesion of the cured film to thefoil is measure by the Tesa tape test.

curing rate curing rate conc (m/min) for (m/min) for ad- photoinitiator(%) solubility surface cure through cure hesion Compound of 6.0 + 20040 + example 1 Irgacure 369 6.0 + 170 90 +

1. Photoinitiators of the formula I

wherein n is 1 or 2; L is a linker; X is —O—, —S— or —NR₃₂—; Z is adirect bond, —CH₂—, —O—, —S— or —NR₁₀—; R₁ is (a) linear or branchedC₁-C₁₂-alkyl, which is unsubstituted or substituted by one or more ofthe groups C₁-C₄-alkyoxy, phenoxy, halogen or phenyl; (b) a radical ofthe formula

(c) a radical of the formula

where q is 0, 1, 2 or 3; or (d) a radical of the formula

where Ar is phenyl, which is unsubstituted or substituted by one or moreof the groups halogen, OH, NO₂, —N(R₁₀)₂, C₁-C₁₂-alkyl, C₁-C₄-alkyl thatis additionally substituted by OH, halogen, N(R₁₀)₂, C₁-C₁₂-alkoxy,—COO(C₁-C₁₈-alkyl), —CO(OCH₂CH₂)_(n)OCH₃ or —OCO(C₁-C₄-alkyl);C₁-C₁₂-alkyoxy, C₁-C₄-alkyoxy that is additionally substituted by—COO(C₁-C₁₈-alkyl) or —CO(OCH₂CH₂)_(n)OCH₃; —OCO(C₁-C₄-alkyl),C₁-C₈-alkylthio, phenoxy, —COO(C₁-C₁₈-alkyl), —CO(OCH₂CH₂)_(n)OCH₃,phenyl or benzoyl; where n is 1-20; R₂ if n is 1, independently of R₁has one of the meanings of R₁; or R₁ together with R₂ forms a ring ofthe formula

where m is 1 or 2; R₂ if n is 2, is a direct bond, C₂-C₁₆-alkylene,cyclohexylene, xylylene, dihydroxyxylylene, C₄-C₈-alkenediyl,C₆-C₁₀-alkadienediyl or dipentenediyl; R₃ is hydrogen, C₁-C₁₂-alkyl,C₂-C₄-alkyl substituted by one or more of the groups hydroxy,C₁-C₄-alkoxy, —CN, —COO(C₁-C₄-alkyl); C₃-C₅-alkenyl, C₅-C₁₂-cycloalkylor C₇-C₉-phenylalkyl; R₄ is C₁-C₁₂-alkyl, C₂-C₄-alkyl substituted by oneor more of the groups hydroxy, C₁-C₄-alkoxy, —CN, —COO(C₁-C₄-alkyl);C₃-C₅-alkenyl, C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, phenyl; or R₄ andR₂ together is C₁-C₇-alkylene, C₇-C₁₀-phenylalkylene, o-xlylene,2-butenylene or C₂-C₃-oxa- or azaalkylene; or R₄ and R₃ together isC₃-C₇-alkylene that may be interrupted by —O—, —S—, —CO— or —N(R₁₃)— andsubstituted by hydroxy, C₁-C₄-alkoxy or 'COO(C₁-C₄-alkyl); R₅ ishydrogen or C₁-C₄-alkyl; or R₅ together with R₃₀ is C₁-C₂-alkylene; R6is hydrogen, C₁-C₈-alkyl or phenyl; R₇, R₈ and R₉ independently of eachother are hydrogen or C₁-C₄-alkyl, or R₇ and R₈ together areC₃-C₇-alkylene; R₁₀ is hydrogen, C₁-C₈-alkyl, C₃-C₅-alkenyl,C₇-C₉-phenlyalkyl, C₁-C₄-hydroxyalkyl or phenyl; R₁₁ and R₁₂independently of each other are hydrogen or C₁-C₄-alkyl, or R₁₁, and R₁₂together are C₃-C₇-alkylene; R₁₃ is hydrogen, C₁-C₁₂-alkyl, which may beinterrupted by one or more —O— or C₃-C₅-alkenyl, C₇-C₉-phenylalkyl,C₁-C₄-hydroxyalkyl, —CH₂CH₂CN, —CH₂CH₂COO(C₁-C₄-alkyl), C₂-C₈-alkanoyl,or benzoyl; R₃₀ and R₃₁ independently of one another are hydrogen,C₁-C₁₈-alkyl or C₁-C₁₈-alkyl substituted by hydroxy, C₁-C₄-alkoxy,—O—CO—(C₁-C₄-alkyl), —CN and/or —COO(C₁-C₄-alkyl); C₃-C₁₈-alkenyl,C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, C₂-C₁₈-alkanoyl, benzoyl ornorbornenoyl; or C₂-C₁₈-alkanoyl, benzoyl or norbornenoyl substituted byC₁-C₄-alkoxy, —NR₃₃R₃₄, —SR₃₅, —COOH or —COO(C₁-C₄-alkyl); or benzoyl ornorbornenoyl substituted by hydroxy, or C₃-C₅-alkenoyl,—SO₂—(C₁-C₁₂-alkyl) or —SO₂—(C₁-C₁₂-alkylphenyl); or —CO—NH—C₁-C₁₂-alkylor —CO—NH—(C₀-C₁₂-Alkylen)—N═C═O optionally interrupted by one or twophenylene, methylphenylene, phenylene-O-phenylene, cyclohexanediyl,methylcyclohexanediyl, trimethylcyclohexanediyl, norbornanediyl,[1-3]diazetidine-2,4-dione-1,3-diyl,3-(6-isocyanatohexyl)-biuret-1,5-diyl or5-(6-isocyanatohexyl)-[1,3,5]triazinan-2,4,6-trion-1,3-diyl; or R₃₀ andR₃₁ together with the group −N−L−X form cyclic structures selected from

R₃₂ is hydrogen, C₁-C₁₈-alkyl or C₁-C₁₈-alkyl substituted by hydroxy,C₁-C₄-alkoxy, —O—CO—(C₁-C₄-alkyl), —CN and/or —COO(C₁-C₄-alkyl);C₃-C₁₈-alkenyl, C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, C₂-C₁₈-alkanoyl,benzoyl or norbornenoyl; or C₂-C₁₈-alkanoyl benzoyl or norbornenoylsubstituted by hydroxy, C₁-C₄-alkoxy, —NR₃₃R₃₄, —SR₃₅, —COOH or—COO(C₁-C₄-alkyl); or C₃-C₅-alkenoyl, —SO₂—(C₁-C₁₂-alkyl) or—SO₂—(C₁-C₁₂-alkylphenyl); or —CO—NH—C₁-C₁₂-alkyl or—CO—NH—(C₀-C₁₂-Alkylen)—N═C═O optionally interrupted by one or twophenylene, methylphenylene, phenylene-O-phenylene, cyclohexanediyl,methylcyclohexanediyl, trimethylcyclohexanediyl, norbornanediyl,[1-3]diazetidine-2,4-dione-1,3-diyl,3-(6-isocyanatohexyl)-biuret-1,5-diyl or5-(6-isocyanatohexyl)-[1,3,5]triazinan-2,4,6-trion-1,3-diyl; R₃₃ and R₃₄independently of one another are hydrogen, C₁-C₁₂-alkyl,C₂-C₄-hydroxy-alkyl, C₃-C₁₀-alkoxyalkyl, C₃-C₅-alkenyl,C₅-C₁₂-cycloalkyl, C₇-C₉-phenylalkyl, phenyl, C₂-C₁₈-alkanoyl orbenzoyl; or R₃₃ and R₃₄ together are C₂-C₈-alkylene optionallyinterrupted by —O—, —S— or —NR₃₆—, or are C₂-C₈-alkylene optionallysubstituted by hydroxy, C₁-C₄-alkoxy, —O—CO—(C₁-C₄-alkyl), or—COO(C₁-C₄-alkyl); R₃₅ is C₁-C₁₈-alkyl, hydroxyethyl,2,3-dihydroxypropyl, cyclohexyl, benzyl, phenyl, C₁-C₁₂-alkylphenyl,—CH₂—COO(C₁-C₁₈-alkyl), —CH₂CH₂—COO(C₁-C₁₈-alkyl) or—CH(CH₃)—COO(C₁-C₁₈-alkyl); R₃₆ is hydrogen, C₁-C₁₂-alkyl optionallyinterrupted by one or more no adjacent —O-atoms, C₃-C₅-alkenyl,C₇-C₉-phenylalkyl, C₁-C₄-hydroxyalkyl, —CH₂CH₂CN,—CH₂CH₂COO(C₁-C₄-alkyl), C₂-C₁₂-alkanoyl or benzoyl; with the provisothat the following compounds are excluded:


2. Photoinitiators according to claim 1, wherein n is 1 or2; L is alinker; X is —O—, —S— or —NR₃₂—; Z is a direct bond; R₁ is (a) linear orbranched unsubstituted C₁-C₁₂-alkyl; (b) a radical of the formula;

or (d) a radical of the formula

wherein Ar is phenyl, which is unsubstituted or substituted by one ormore of the groups NO₂, —N(R₁₀)₂, C₁-C₄-alkyl, C₁-C₄-alkoxy,C₁-C₄-alkylthio, phenoxy; R₂ if n is 1, independently of R₁ has one ofthe meanings of R₁; R₂ if n is 2, is C₂-C₈alkylene; R₃ is C₁-C₄-alkyl,C₂-C₄-alkyl substituted by hydroxy, C₁-C₄-alkoxy; C₃-C₅-alkenyl; R₄independently of R₃ has one of the meanings of R₃; or R₄ together withR₃ is C₄-C₅-alkylene that may be interrupted by —O—, —N(R₁₃)—; R₅ ishydrogen; R₆, R₇, R₈ and R₉ independently of each other are hydrogen ormethyl; R₁₀ is hydrogen, C₁-C₄-alkyl or C₃-C₅-alkenyl; R₁₃ is hydrogenor C₁-C₄-alkyl; R₃₀ and R₃₁ independently of one another are hydrogen,C₁-C₁₂-alkyl; or C₂-C₆-alkyl substituted by hydroxy, C₁-C₄-alkoxy,—O—CO—(C₁-C₄-alkyl), or —COO(C₁-C₄-alkyl); allyl, cyclohexyl orC₇-C₉-phenylalkyl; or C₂-C₁₂-alkanoyl, benzoyl or norbornenoyl; orC₂-C₁₂-alkanoyl, benzoyl or norbornenoyl substituted by C₁-C₄-alkoxy,-COOH or -COO(C₁-C₄-alkyl); or C₃-C₅-alkenoyl; or —CO—NH—C₁-C₁₂-alkyl or—CO—NH—(C₀-C₁₂-alkylen)—N═C═O, optionally interrupted by one or twophenylene, methylphenylene, phenylene-O-phenylene, cyclohexanediyl,methylcyclohexanediyl, trimethylcyclohexanediyl, norbornanediyl,[1-3]diazetidine-2,4-dione-1,3-diyl,3-(6-isocyanatohexyl)-biuret-1,5-diyl or5-(6-lsocyanatohexyl)-[1,3,5]triazinane-2,4,6-trione-1,3-diyl; R₃₂ ishydrogen or C₁-C₁₂-alkyl.
 3. Photoinitiators according to claim 2,wherein n is 1 or 2; L is linear or branched C₂-C₁₈-alkanediyl; X is—O—; Z is a direct bond; R₁ is (a) linear or branched unsubstitutedC₁-C₃-alkyl; (b) a radical of the formula;

(d) a radical of the formula

where Ar is phenyl, which is unsubstituted or substituted by CH₃—NO₂ or—N(R₁₀)₂; R₂ if n is 1, independently of R₁ has one of the meanings ofR₁; R₂ if n is 2, is C₂-C₈alkylene; R₃ is methyl, R₄ is methyl or R₄together with R₃ is C₅-alkylene that is interrupted by —O—; R₅ ishydrogen; R₆, R₇, R₈ and R₉ are hydrogen; R₁₀ is hydrogen; R₃₀ and R₃₁independently of one another are hydrogen, C₁-C₁₂-alkyl; or C₂-C6-alkylsubstituted by hydroxy; C₁-C₄-alkoxy, —O—CO—(C₁-C₄-alkyl), orC₃-C₅-alkenoyl.
 4. Photoinitiators according to claim 1, wherein n is 1or 2, R₁ is benzyl, 4-aminobenzyl, propyl or allyl and R₂ is ethyl or isC₂-C₈alkylene.
 5. A composition comprising (A) at least oneethylenically unsaturated compound; (B) a photoinitiator of formula I asdefined in claim
 1. 6-7. (canceled)
 8. Photoinitiators according toclaim 2, wherein n is 1 or 2, R₁ is benzyl, 4-aminobenzyl, propyl orallyl and R₂ is ethyl or is C₂-C₈alkylene.
 9. Photoinitiators accordingto claim 3, wherein n is 1 or 2, R₁ is benzyl, 4-aminobenzyl, propyl orallyl and R₂ is ethyl or is C₂-C₈alkylene.
 10. A method forphotopolymerization of ethylenically unsaturated compounds or mixturescontaining ethylenically unsaturated compounds which method comprisespreparation of a composition comprising ethylenically unsaturatedcompounds and compounds of the formula I according to claim 1 andexposure of the composition to electromagnetic radiation.
 11. A methodfor the preparation of multifunctional photoinitiators by reaction ofcompounds of the formula I as defined in claim 1 with appropriatereagents.
 12. A method for the preparation of multifunctionalphotoinitiators according to claim 11 by reaction of compounds of theformula I as defined in claim 1 with acids, acid halides, acidanhydrides, lactones, aldehydes, ketones, isocyanates, sulfonic acidchlorides, alkyl halides, alkyl sulphonates, epoxides, acrylates,methacrylates, amines, alcohols and thioalcohols.